This time my mums chair she was sitting on was shaking violently. I was outside and didnt notice as was walking around. Last time about four years ago it was a larger one and we heard a noise like a jet plane, and what seemed like ten seconds later the living room floor suddenly jumped down. It felt like it went down about a foot and a half to two feet. Was like we were in a lift. Yet nearby Gower had shaking that time. There is a fault line and I believe we are right on the edge between two plates here to have the sudden drop we had before.